Manufacture of steel by the pneumatic process.



PATENTED FEB. 25, 1908 A. TROPENAS. MANUFAGTURB OF STEEL BY THEPNEUMATIC PROCESS APPLICATION FILED JAN, 29, 1907.

1 a w 4. M V A m2 apgx 1m burn]? 0 mpe A. n Lilo wb 1M}. 1. coma'nex tumcarbon 1m icnnl be TENUNTEL Technicians know Well enmlgh that the onlyserious element that csnbe taken as a basis to' determine the precisemoment for stoppin the blowin is observation of the certainty aspecified grade ol steel.

The above explanation will now enable me to point out the novelty of themethod,

' hereinafter described, relating to e processof fluid and containing atleterimnecl sired percentage of carbon.

manufacturing steel: in small charges Which I have discovered aftervarious experiments, and by which, While getting a very h igh final,tern. erature, the carbon flame remains visi le up to the complete endof the process and allows steel to be easily mamn'actured even invenysmall charges, reliably hot and and. i e- I .Will now describe my methodfor the treatment of Plg IiTGH m'an acnl lme l conlverter. To csrry outthis method, any sniteble type of converters can be utilized. A

converter may be iised such as represented in the sectional VlBW of theaccompanying sheet of drawings, which is'a vertical section Abeing theWroughtironor steel shell, and B the refractory SlliClOllS lining. Thevessel mounted on truimions C, and can turn upon them." A Wind box I);is connected with one of the hollow trunnions, through which comes theblast from the blowing engine; the general construction of the shellhaving no particularnovelty and being of the type adopted for'orclinaryconverters, it is not necessary to describe it in detail.

The bottom of the vessel OI'CIllCllOlB is so designed that the metallic.bath has consider able depth. The twyers, F, conveying; the

blast through thelining into the vessel, are

placed so as to be just above the level. of the 'metallic bath when themolten charge-is in,

before starting blowing.

In carrymg out my improved process, 1 prefer to use hematite pig-ironcontaining aslittle silicon as possible. ll this low .silicious ironcannot be obtained, a mixture of pig-iron and steel scrap may be chargedinto the cupola so as to lower the percentage of silicon in the metalpoured into the con verter.

When the pig-iron or mixture ol pig-iron and scrap has been melted in anordinary oupola, it is poured as usual into the coin verter previouslyheatedbefore the first operation. The converter is turned so as to bringthe twyers justabove the level of percentage of the silicon in the metalcharged ture of the metallic bat adderl silicon is oxidizedfalongwiththe'ca bon, and this gradually, while the silicon seaess themetallic bath, and theblo'wing started.

On account of the, low percentage of silicon in the metal, the firstperioth t'. e.,'the periofl without flame, is very shoat. As soonas thesecond perio'rl begins, 11. 6., immediately following the appearancelofthe carbon flame at the mouth of the, vessel, a small quantity ofsilicon, in the form of highly sillcious igiron or lerro-silicon,Varying with the initial in the vessel, is thrown into the converterWithout stopping blowing. If this 7 addition" of silicon bensed cold, itshould bethro'wn in almost assoon as the carbon llame' appears.- If theaddition be thrown in hot,-itmay be added 'a 'littlelater but very; soonafterthe appearanceof the carbon flame. Thisarldition does not'generallyexceedv in weight five per cent'of the charge, but'may be incertaincases, more or less The blow: ing is continued Without stoPp'ageof any sort until the name dros; this {lroppingis very characteristic anveryclear'." The v final addition of ferroqnanganese is made in intomolds. V I in starting the operation the nsna-lrvay amlthe steel isready lupus;

tion of the first period, (Without llnmehkjis. recluceclto a minimum andtheioxirlation of" iron, and the Wear of the refractory liningarelikewise reduced to'a minimum, making;

with metallic i bath oflow percentage of Sill flflll, thellnieg 'fmetliately after the carbon flame has made its appearance at the monthof theconverter (not before or sometime after} all the silicoiiadded-for? increasing the temperature of the bath is utilized under thebest conditions Experiments have shown that it the bath contains a highpercentage iii-silicon; the, first period, without flamelis 11inchprolonged and the greatest part, ofheetf produced bythe'oxidationo'lztlle silicon is absorbed by the jmeltin ol? the. remotely liningWithout increaslnfit the final. tsniperalEn starting, asjspeoified,withlo.

.. ilicions i iron and adcling silicony only immediately alter theappeai ance of thecarbon flame,:thea

added, is transmittal in meltiligfto the metallic bath. The addedsilicon moreover,

becomes completely melted before the clropplug of the carbon flame,&I1(l*Wl'l8Il the flame disap ears, all the silicon added has been competely eliminated. The silicon being clissolvecl into the bath does notallect'in the least the evolution of progression of the car bon flamewhich, can be observed Without any (lilliculty so that the operation.can be stopped at the right moment with absolute certainty, While thetemperature of thebath has been greatly increased, The steel contains notrace of the supplementary silicon 7 capacity of di'll'erent systemswith the View assess which has been added, and is' not overoxidizeol;con'secpoei'itly it is then possible to make exactly the final additionof manganese, and to'reach the percentage of carbon for a given gradeorquality.

{The experiments made in a great number of blows have shown that withthe use of the process above described, it is possible withacontgerterhf ahalt ton capacity to obtain always, the same givenpercentage of carbon anilfthe same quality of metal without app'reciablepractical Variation, and that the steel thus produced. is sufficientlyfluid. to he carried in small ladies and poured into very small moldsWithout waste and Without the formation of skulls.

Experiments made in converters of small of obtaining steel always of thesame required quality, hot and fluid enough to cast small articles, haveshown (a) that an addi' 'tion ofrsilicon made before the appearance ofthe carbon flame retards, or prolongs, the time of its operation andreduces a had operation; (b) that an adc ition of silicon made near theend of the operation at about the moment of the dro ping of the flame, alittle before or after, tlizprives the operator of the reliable signsfurnished the flame for the stoppage or the operation. at right moment,and does not secure the accuracy needed in. general practice to obtainthe re-.

quired grade of steel; (0) that only the addition of cold silicon madeimmediately after the appearance of the carbon flame, or which is thesame, the same addition of silicon made hot or melted and added-a littlelater, but always a long time before the disappearance of the flame,gives a good result, certain and accurate I. claim as my invention As animprovement in the manufacture of steel by the pneumatic process,blowing the charge until the appearance of the carbon flame, addingasinall percentage of silicon immediately after the appearance of such

